Selective attention

Question 1

Broca’s area

Answer 1

1. located in frontal lobe, left hemisphere
2. primarily responsible for speech production and articulation
3. helps in forming grammatically correct sentences
4. coordinates motor functions needed for speaking

Question 1

Wernicke’s area

Answer 1

1. located in superior temporal gyrus, left hemisphere
2. primarily responsible for language comprehension
3. helps in understanding spoken and written language
4. plays a role in meaningful sentence formation

Question 2

evidence for specialised structure-computing module in our brains

Answer 2

1. Broca’s aphasia and comprehension difficulties - while Broca’s aphasia is typically associated with difficulty in speech production, this slide emphasises that some Broca’s aphasia patients also struggle with comprehension, comprehension deficits mainly appear in syntactically complex sentences
2. challenges with complex sentence structure - sentences requiring hierarchical parsing and spatial reasoning, which Broca’s aphasia patients often find difficult

Question 3

problems with reversible sentences

Answer 3

1. sentences with multiple nouns, both nouns can be subjects or objects, word order and grammatical marker are crucial to determine meaning
2. Broca’s aphasia patients often rely on semantic cues rather than syntax, so they may struggle to correctly interpret who is performing the action
3. supports the idea that Broca;s areas is crucial not only for speech production but also for understanding syntax and sentence structure
4. patients with broca’s aphasia rely more on meaning rather than syntax, leading to difficulties in interpreting sentences where meaning depends on grammatical structure rather than word meaning

Question 4

perception and attention

Answer 4

1. perception - successful perception involves educated guesses about the world
2. attention - we cannot attend to everything so we attend to some things not others, we miss a surprising amount

Question 5

dividing attention between voices

Answer 5

1. we cannot understand/remember the contents of two concurrent spoken messages
2. best we can do is alternate between attending selectively to the speakers

Question 6

focused attention to one of two simultaneous speech messages

Answer 6

1. shadowing - one of the messages is successful if the messages differ in physical properties, not successful if they differ only in semantic content
2. participants notice physical changes not semantic changes in unattended messages
3. word repeated 35 times in unattended message not remembered better than word heard once

Question 7

attentional selection precedes lexical identification and access to meaning

Answer 7

1. it seems that unattended words are filtered out early, after analysis of physical attributes, before access to identity/meaning
2. so, though aware of unattended speech as sound with pitch, loudness and phonetic characteristics, we do not seem to process their identity or meaning
3. if required to extract identity or meaning from two sources, P has to switch the attention filter between them - slow and effortful process

Question 8

broadbent’s filter model

Answer 8

1. sensory features of all speech sources are processed in parallel and store briefly in sensory memory
2. a selective filter is directed to one source at a time
3. filter is early in processing, so that only information that passes through the filter achieves recognition, activation of their meaning, representation in memory, control of voluntary action
4. 2 additional assumptions - filter is all or none, is obligatory

Question 9

filtering is not all or none

Answer 9

examples of partial breakthrough of meaning of unattended in shadowing experimenter, own name being noticed, interpretation of lexically ambiguous words in attended message influenced by meaning of words in unattended message

Question 10

breakthrough demonstrations and late selection theory

Answer 10

1. theory - both attended and unattended words processed up to and including identification and meaning activation, relevant meanings then picked out on basis of permanent salience or current relevance
2. but doesn’t explain why selection on the basis of sensory attributes so much more efficient than selection on basis of meaning
3. GSR to unattended probe words weaker than to attended

Question 11

filter attenuation theory

Answer 11

1. suggests there is an early filter
2. but it is not all or none - it attenuates input from unattended sources
3. early filtering is an optional strategy not a fixed structural bottleneck

Question 12

vision

Answer 12

1. lots of evidence that when you display an array of objects very briefly, we can select which ones to report on the basis of their physical properties
2. however such displays are rather unrepresentative or normal vision, where we are dealing with dynamic visual events
3. one difference between visual and auditory attention is that while we can’t select a sound to attend to by pointing our ears, we do this with vision
4. we can also move attention independently of fixation
5. an influential way of proving this voluntary movement was introduced by mike posner

Question 13

Posner et al - the attentional spotlight

Answer 13

1. endogenous arrow cue enables you to shift your attention to the expected location without moving your eyes
2. on average, responses were faster to stimulus when it occurs in the expected and therefor attended location and slower to a target in the unattended location
3. so the processing of the stimuli in the attentional spotlight enjoys an efficiency gain, and stimulus outside the spotlight an efficiency penalty
4. orienting of attention was voluntary, driven by expectation

Question 14

endogenous vs exogenous shifts

Answer 14

1. attentional spotlight also gets attracted involuntarily - to an isolated and salient change somewhere in the visual field
2. instead of an arrow being presented before the stimulus, one of the boxes suddenly flashed and this was completely random with respect to which side the stimulus was on
3. so a sudden onset or movement in the visual field automatically captures attention
4. this automatic stimulus driven - exogenous - shift of attention happens very quickly
5. the endogenous or voluntary shift of attention is slower it takes half a second or more to shift
6. Posner’s paradigm has recently been used in combination with measures of brain activation to address the question of how early in the processing of visual information this selective focusing happens

Question 15

endogenous cueing

Answer 15

1. voluntary, top down
2. attention is guided internally based on expectations and prior knowledge
3. stimulus location is indicated by a cue
4. the cue is valid 80% of the time, encouraging voluntary allocation of attention
5. reaction time is measured - faster for expected location, slower for unexpected locations

Question 16

exogenous cueing

Answer 16

1. stimulus-driven, bottom up
2. attention is captured automatically by a sudden visual change
3. even if the change does not predict the target location, RT is still faster at the cued location due to automatic attraction of attention
4. timing differences - exogenous shift occur very fast, endogenous shifts take several hundred milliseconds

Question 17

voluntary attention to a spatial locus modulates early components of ERP in extra striate visual cortex

Answer 17

1. PI component of the event-related potential is enhanced when attention is directed to a spatial location
2. the graph shows how attention to the left enhances the PI response compared to ignoring the left
3. the topographic brain maps show increased activity in the extra striate visual cortex when attending to a stimulus
4. early selection in the primary visual cortex and LGN - visual processing follows a hierarchical pathway, retina-LGN-V1-Extrastriate cortex
5. experiment described involved fixating on a central point, digits appearing at fixation, high or low contrast checkerboards appearing peripherally requiring attention shifts

Question 18

early selection in primary visual cortex and even LGN

Answer 18

1. while fixation maintained on central point - series of digits appears at fixation and high or low contrast checkerboards appear in left and right periphery
2. P either counts digits at fixation, or detects random luminance changes in left or right checkerboard
3. fmri bold signal in LGN/V1 voxels that react to checkerboard luminance change is greater with attention directed to that side than with attention fixation
4. so at least some selection occurs very early in processing

Question 19

visual selection

Answer 19

1. is not all or none, there is a gradient of enhancement/suppression across the visual field
2. is an optional process - the size of the attended area is under voluntary control
3. participant were asked to attend either a central letter, the whole word, occiasionally a probe display appeared, requiring classification of a single lette
4. reaction time was faster for probes near the center when attention was focused on a single letter, RT was faster for probes across the whole word when attention was spread out to process the entire word
5. this suggests flexibility in attentional focus it can be narrowly focused or broadly distributed

Question 20

efficiency of early selection depends on processing load

Answer 20

1. flanker task - press left key for little x right key for little z. on midline, ignore big letter above or below mid-line
2. incongruent distractor slows response relative to congruent - if processing load is low
3. but not is processing load is increased by requiring Ps to pick target out of several irrelevant letters
4. if attention is fully occupied with a demanding task - irrelevant distractors have less impact
5. supports load theory of attention - when cognitive load is high, there is less leftover attention for distractions

Question 21

visual attention in dynamic scenes - inattentional blindness

Answer 21

1. experiments by daniel simon require participant to attend closely to one coherent stream of visual events on the screen, spatially overlapping with another stream
2. highly salient events in the unattended stream are missed by a large proportion of the participants
3. hence the events of the unattended stream, though happening in a part of the visual field fixated by the participant processed to the level of meaning

Question 22

limiting factors of memory

Answer 22

1. attention
   .2 working memory capacity
2. speed of processing

Question 23

multi tasking and cognitive capacity

Answer 23

1. even when we do just one task, there are limits to cognitive capacity - all processes take time, there are limits to the input any one processes can handle, representational/storage capacity is limited
2. capacity limits become even more obvious when resources must be shared between tasks - have to get more than one task done in a certain time, at least some tasks are time critical, so we must either do them simultaneously or switch back and forth between them

Question 24

study on relative risk of mobile phone use and drinking

Answer 24

1. driver in simulator - follows pacer car in slow lane of interstate for 15 mins, tries to maintain distance, pacer car brakes occasionally 2. baseline vs alcohol vs causal talk on hand-held or hands-free mobile 3. mobile phone users - slower reactions, more tail-end collisions, slower recovery 4. alcohol - more aggressive driving 5. no significant difference between effects of talking on hand-held and hands free

Question 25

further driving simulator studies show

Answer 25

1. just talking on hands free mobile phone - reduced anticipatory glances to safety critical locations, reduced by later recognition memory of objects in driving environment, increased probability of an unsafe lane change 2. does talking to passenger have the same effect, simulator studies show that passengers are sensitive to drivers load, passengers help spot hazards

Question 26

measuring dual task interference in the lab

Answer 26

1. just two tasks, designed for measurement and manipulation 2. typically measures performance on tasks A and B alone, on A and B combines

Question 27

possible sources of dual task interference

Answer 27

1. slower and less accurate performance in dual task conditions might be attributable to competition for use of specialised domain specific resources, parts of body, brain modules, competition for use of general purpose processing capacity, limited capacity of executive control mechanisms that set up and manage the flow of information through the system

Question 28

competition for domain specific resources

Answer 28

1. certain cognitive tasks interfere with each other when they rely on the same specialised resources 2. auditory processing - listening to two speech streams at once impairs comprehension as both rely on speech perception mechanisms 2. visuo spatial working memory - performing a spatial tracking task makes it harder to use visual imagery for memory tasks 3. dual task interference occurs when tasks require the same sensory, response or central processing mechanisms 4. however, if the information rate is low enough, resources may be efficiently swtiched between tasks

Question 29

competition for a general purpose processor

Answer 29

1. analogous to standard late 20th century digital computer with its single CPU 2. assumed to be required for pattern recognition, access to memory, decision making, action selection, awareness 3. the central processing model compares cognitive processing to a single CPU computer 4. a single processing unit is responsible for pattern recognition, memory access, decision making, action selection, awareness 5. Posner - linked this central processor to consciousness, this model suggests that any task requiring central processing competes for the same limited resources, leading to task interference

Question 30

a general purpose resource pool

Answer 30

1. Kahneman - proposed a pool of general purpose resources that is shared among concurrent tasks 2. the capacity of this general purpose resource might vary over people and within people 3. level of sustained attention - diminishes with boredom or fatigue, increases with time of day

Question 31

sharing capacity

Answer 31

1. sum of capacity demands does not exceed available total - no interference 2. sum does exceed - interference, increasing the difficulty of one task should reduce the capacity available for the other task 3. hard to know how much capacity a giver task should use 4. so test theory by using pairs of tasks for which it seems obvious that each would require all the most of the central capacity

Question 32

a case of demanding tasks combined without interference - allport

Answer 32

1. university of reading year 3 music students 2. task A - sight read grade 2 or 4 piano pieces 3. task B - shadow prose from austen novel or text on old norser 4. relatively little practice 5. experiment - two sessions of 2x1 minute dual task for each combination of easy and hard and 1 minute sight reading or shadowing alone 6. rate of shadowing and number of shadowing errors were no different with and without concurrent sight reading 7. concurrent shadowing also did not increase sight reading errors 8. more shadowing errors for harder text and more sight reading errors for grade 4 pieces - shadowing performance not influenced by difficulty of music piece, sight reading performance not influenced by difficulty of prose shadowed

Question 33

the radical claim - no central general purpose processor/resource

Answer 33

1. allport - rejected the idea of a single "central processor", instead tasks rely on separate, non overlapping modules 2. if tasks engage different brain networks, they can be performed simultaneously with little interference 3. this challenges Kahneman's general resource theory, which posited a shared attentional post 4. but even when tasks use completely different modules, some interference may arise due to coordination and control demands

Question 34

driving and phone conversation

Answer 34

1. the case that driving/navigation and conversation require the use of different modules is true and false 2. they use different input and output modalities, but both require construction of a mental model 3. the construction of the mental model for driving can be interfered with by a conversation that asks the driver to think about a visuo spatial arrangement or imagine movements

Question 35

the importance of practice

Answer 35

1.Tasks which cannot be combined without interference become easier to combine with practice 2 Spellke, Hirst and Neisser - after 85 hours of practice at reading stories at the same time as writing to dictation and then reading stories concurrent with writing category of spoken words, some participants showed little dual task interference 3. Because practicing one task automates it, reduces need for executive control of the constituent processes, practicing combining tasks develops optimal control strategies for combining that particular task pair

Question 36

Broadbent's objection to allport-type experiments

Answer 36

1. With pairs of continuous tasks like shadowing and sight reading there is some predictability in the input, a substantial lag between input and output 2. So there could still be a central processor switching between the two tasks, while processor services one task, input/output for the other task could be stored in WM buffers 3. test - processor-switching should be revealed if we use concurrent tasks with very small lags between input and output, and the next stimulus unpredictable

Question 37

psychological refractory period

Answer 37

1.Two choice reaction-time tasks, stimulus onsets separated by a variable, very short, interval 2. Allport argued against a single central processor suggesting that tasks can be performed independently if they use different cognitive modules 3. Broadbent disagreed, pointing out that some continuous tasks allow for anticipation which may reduce interference 4. A time lag between input and output means that working memory buffers can temporarily store information while the processor switches between tasks 5. Processor switching may still be necessary for task coordination 6. Test is to reveal processor switching, we need concurrent tasks with unpredictable timing, reaction time tasks where the next stimulus is not predictable 7. PRP demonstrates a fundamental limit in multitasking, supporting the idea of a central bottleneck 8. Two choice reaction-time tasks occur in quick succession, S1-R1, after a short delay (SOA), S2-R2 When SOA is short, RT1 remains stable, RT2 is delayed 9. As SOA increases, RT2 speeds up because the bottleneck is cleared Response selection is the processing bottleneck - only one response selection process can occur at a time, if a second stimulus is identified while the first response is being selected, it must wait until the first response is completed, this explains why RT2 is delayed at short SOAs

Question 38

conclusions

Answer 38

1. Real multitasking is rare to achieve, it is better to focus on one task at the time 2. Switching attention constantly consumes energy and drains cognitive resources 3. Executive control is needed to do the coordinating, scheduling, prioritising and these mechanisms have capacity limits, being constantly on alert leads to fatigue, burn outs

Question 39

early selection an option not a structural bottleneck

Answer 39

1. After practice, people can detect targets equally well whether they have to monitor one or both ears 2. This suggests that early selection is flexible and not necessarily a bottleneck 3. Unless selective understanding/repetition of one message is required 4. When selective repetition is required, attentional resources are limited, making detection of other stimuli harder